Preheating torch and method of operating the same



July 14, 1925.

E. H. SMITH PREHEATING TORCH AND METHOD OF OPERATING THE SAME Filed Dec. 26. 1925 [N vE/v ToR ZZMER 61W TH zr mfimv hwm Patented July 14,1925.-

ELMER H. SMITH, OF MINNEAPOLIS, MINNESOTA.

PREHEATING TORCH AND METHOD or ornm'rme THE SAME.

Application filed December 26, 1923. Serial No. 682,768.

To all whom it may concern:

Be it known that I, ELMER H. SMITH, a citizen of the United States, resident of Minneapolis, county of Hennepin, and State of Minnesota, have invented certain new and useful Improvements in Preheating Torches and Methods of Operating the Same, of which the following is a specification.

My invention relates to preheating torches in which a suitable'liquid fuel such as kerosene is converted into a combustible vapor for the heating flame. Torches of this kind are frequently used in places where the temperature is comparatively high and sometimes in places where the temperature is very low. Evidently in a high atmospheric temperature the walls and vaporizing coil will become heated to such a degree of intensity that the flame of the burner will be shortened on account of the delivery of a smaller volume of fuel and the efficiency of the torch will thereby be reduced. When the torch is used in a very cold place, the coil and the walls of the torch will be so affected that proper vaporization will be retarded.

The object therefore of my invention is to provide a torch having means for reducing the temperature of the coil and walls of the torch or to correspondingly raise the temperature when it is desirableto do so in the operation of the device.

The invention consists generally-in various constructions and comblnations all as hereinafter described and particularly pointed out in the claims.

In the aocompanving drawings forming part of this specification.

Figure 1 is a longitudinal sectional view through a preheating torch embodying my invention showing it adapted for reducing thetemperature of the vaporizing coil;

Figure 2 is a similar view showing how the torch may be adapted for-raising the temperature of the coil; v

Figure 3 is a sectional view on the line 3-3 of Figure 2.

In the drawing, 2 represents a. casing of suitable material, preferably cylindrical in form, having a head 3 fittingwithin ne end with an opening therein substantlally concentric with the bore of the casing and provided with an annular flange 4, preferably having converging walls, and a discharge opening 5 through which the flame is rojected upon the surface to 'be heated.

t the other end of the casing is a head 6 fitting within the open end of the casing and provided with a duct 7 which communicates at its outer end with a passage ranged in a block 9 which closes the end of a pipe 10 that is tapped or otherwise mountedon the outer end of the head 6. A rod 11 has a needle valve 12 at one end which has threaded connection with the walls of the passage 8 in the block 9 and provided with a series of longitudinal ducts .13

this rod 11 is moved in to the limit of its stroke theneedle valve will close the passage 8 and shut off the flow of liquid fuel to the duct 7. A pipe 14: connects the duct 7 with a passage 15 in the head 3 and saidv passage extends around within said head to the opposite side thereof and is connected to one end of a vaporizer preferably a coil 16 that is arranged within the casing 2. The other end 17 of said coil communicates with a passage 18 in the head 6 which leads to the burner nozzle 19 and through which the vaporized fuel is delivered to said nozzle. 'A ring 20 is fitted within the open end of the casing 2 and is provided with a series of ports 21 and a central opening 22 that is opposite the discharge end of the nozzle 19. A damperring 23 is mounted to 23 and exposingthe openings 21 or closing them. The rings 20 and 23 form in effect a damper by means of which air may be admitted to the casing or shut oif, as may be desired, in the operation of the torch.

Opposite the opening-22 and within the vaporizing coil I provide a tube 25, preferably tapered, having its smaller end opposite and adjacent the opening 22 and its larger end near the outlet or outer end of the coil; a space being provided between the smaller end of the tube and the adjacent ring 20. When the damper is closed entirely, air for combustion will flow through the opening 22 and mingle with the vapor from the burner,'the flame being projected through'the tube 25 and a considerable distance beyond the outer end of the torch. If the coil and tllQJWflllS of the casing become heated to a high degree so walls of the vaporizingcoil.

that the temperature of the vapor and its expansion are increased beyond the desired point, the operator will open the damper and thereupon a volume of cold air will flow into the space between the casing and the tube and circulate around and cool the llhis is due to the fact that the flow of the vapor produces a vacuum around the outer or larger end of the tube 25 so that when the damper is opened, air will be sucked in through the openings therein and made to flow around the coil to reduce its temperature. Generally the opening 22 is insufficient to supply the tube with air and a supply of air is delivered through the damper openings.

1 have found in actual practice that a casing and coil heated to a red heat can be cooled to the desired temperature in a few moments. It the damper is closed, a vacuum will be formed at the smaller end of the tube which is stronger than the'vacuum at the large end and a suction will be established backwardly between the coil and ator wishes to lower the 1 temperature of the'coil and vapor or raise it. I have found the casing and around the convolutions of the coil and heated airvand the flame and products of combustion will be drawn in' between the coil and the casing and serve to raise the temperature of the coil and the vapor therein, as indicated by the arrow in Figure 2. This is due to the fact that the damper being closed and the air rushing in through the opening 22 and mingling with the gas will form a stronger vacuum T at the smaller end of the tube and set up a backward circulation around the convolutions of the coil. I am thus able, by the manipulation of the danger, to control currents of air at either end of the tube and set up a circulation of cool air in one di rection around the coil or currentsof heated air and flame in the other direction around the coil, depending upon whether the operin actual practice that l -can accurately regulate the flowof cold and heated air around the coil and thus govern the temperature of the vaporizer and vapor according to atmospheric donditions and the place where the torch may be in use.

I claim as my invention:

1. A torch comprising a fluid fuel burner, a vaporizer, a flue within said vaporizer through which the flame of said burner is directed, a casing and means cooperative with said casin and vaporizer for causing the products 0 combustion to flow from the outlet of said flue. backwardly around the vaporizer to heat, the walls thereof.

2. A torch comprising a liquid fuel burner, a vaporizer coil, a flue within said coil through which the flame from said burner is directed, and means for causing the products of combustion to flow from the reac es outlet of said flue backwardly around the convolutions of said coil to heat the walls thereof, said means comprising a wall opposite said burner and provided with a flame opening spaced from said flue intake and damper controlled air intake openings grouped around said flame opening.

3. A torch comprising a liquid fuel.

burner, a casing having intake and outlet openings, a vaporizer within said casing, a flue within said vaporizer through which the flame from said burner is directed to said outlet opening,'s aid casing and vaporizer having an air circulating passage be tween them communicating with the outlet openings of SUd flue and casing, and means adjacent said burner for admitting air tosaid circulating passage to flow outwardly to the outlet opening of said casing through said passage and around said vaporizer to cool it.

d. A torch comprising a liquid fuel burner, a casing having intake and outlet openings, a vaporizer within said casing, a circulating passage being provided between said vaporizer and the wall of said casing,

a flue within said vaporizer through which the flame is directed from said burner, said flue being spaced from said inlet opening and communicating at each end with said circulating passage, means for excluding air from said passage, and causing a suction between said inlet opening and flue when the air intake of said passage is closed and setting up a backward draft in said passage to draw the flames and products of combustion backwardly around the said vaporizer to heat it. e

5. A torchv comprising a liquid fuel burner, a casinghaving an outlet opening .ing of said casing, said damper when open creating a suction atthe outer end of said flue and drawing the cold airinto said circulating passage around the convolutions of said' coil to cool them, and said damper when closed creating a suction between said flue and inlet opening and drawing the flame and products of combustion backwardly through said circulating passage afiound the convolutions of said coil to heat t em.

'6. A device of the class described com-- prising a burner head having a duct therein for communication with a source of lieunease 'uid fuel supply,, a casing having a head at its outer end provided with an outlet opening, and a duct encircling said opening and havingia pipeconnection with the duct in said urner head, a burner tip mounted in said head, a vaporizer coil communicating with the duct, of said casing head and with said burner tip, a flue within said coil, a wall arranged in said casing and having an inletopening opposite said burner tip, a circulating passage bein formed between said. flue and the wall 0 said casing, and communicating with the outlet of'said casing, and a damper device .encircling said inlet opening in said wall .and controlling the admission of air to said circulating passage.

7. A torch comprising a liquid fuel burner, 'a casing having intake and discharge openings, .a vaporizer within said casing, a circulating passage being provided between said vaporizer and easing communicating with said inlet and discharge opening's, a flue within saidvaporizer extending partially therethrough and 'having its outlet opening remote from the outlet opening "of said casing, said burner having means for receiving air for combustion between it and the inlet opening of said casing and said casing having means for admitting or shutting, 011 the flow of cold air to said circulating passa 8. A method of heating a torch vaporizer I which consists in projecting the burner 7 flame through the vaporizer and causingregulated amounts of the products of combustion toflow backwardly into contact with the walls of the vaporizer to"regu-' casing to regulate, the heat of the walls of said vaporizer.

In witness whereof, I have hereunto set myhand this 21st day of December, 1923.

ELMER H. SMITH. 

